Electrodeless bulb, and electrodeless lighting system having the same

ABSTRACT

Disclosed are an electrodeless bulb ( 10 ), and an electrodeless lighting system having the same. The electrodeless bulb ( 10 ) includes; a light emitting unit ( 11, 13 ) having an airtight inside space ( 116, 13   a ); a main discharge material filled in the inside space ( 11   a,    13   a ) of the light emitting unit ( 11, 13 ) and discharged by microwave, for emitting light; a discharge assistant material filled in the light emitting unit ( 11, 13 ), for forming plasma in the inside space ( 11   a,    13   a ) before the main discharge material generates plasma; and a discharge catalyst material filled in the light emitting unit ( 11, 13 ), for inducing initial discharge of the main discharge material and the discharge assistant material. The lighting system improves lighting efficiency of the main discharge material filled in the light emitting unit ( 11, 13 ), and has an eco-friendly characteristic by excluding an environmental contaminant such as mercury.

TECHNICAL FIELD

The present invention relates to an electrodeless lighting system usingmicrowave discharge, and more particularly, to an electrodeless bulb,and an electrodeless lighting system having the same which canfacilitate initial lighting by forming an auxiliary light emitting unitcontaining a discharge assistant material and a discharge catalystmaterial near a light emitting unit of the electrodeless bulb.

BACKGROUND ART

In general, an electrodeless lighting system (plasma lighting system)uses a magnetron. Microwave generated by the magnetron discharges adischarge material in an electrodeless bulb to form a plasma state, andmakes a metallic compound continuously emit light, so that theelectrodeless lighting system can supply high intensity light without anelectrode.

A main discharge material for leading light emission by forming plasmain the operation, such as metal, halogen compound, sulfur, selenium orthe like, a discharge assistant material for forming plasma in a lightemitting unit at the initial stage of light emission, such as an inertgas Ar, Xe, Kr or the like, and a discharge catalyst material for easinglighting by helping initial discharge or adjusting a spectrum of thegenerated light, such as mercury are filled in the electrodeless bulb ofthe electrodeless lighting system.

FIG. 1 is a cross-sectional view illustrating a conventionalelectrodeless lighting system.

Referring to FIG. 1, the conventional electrodeless lighting systemincludes a magnetron 2 mounted in a casing 1, for generating microwave,a high voltage generator 3 for boosting common AC power to a highvoltage, and supplying the high voltage to the magnetron 2, a waveguide4 connected to an outlet unit of the magnetron 2, for transmitting themicrowave generated by the magnetron 2, an electrodeless bulb 5 filledwith the main discharge material, the discharge assistant material andthe discharge catalyst material, for emitting light as the filledmaterial generates plasma by the microwave transmitted through thewaveguide 4, a resonator 6 covered on the front portions of thewaveguide 4 and the electrodeless bulb 5, for resonating the microwavewith a predetermined resonating frequency, a reflecting shade 7 forhousing the resonator 6, and intensively reflecting the light generatedby the electrodeless bulb 5 straight, a reflector 8 mounted in theresonator 6 and positioned at the rear side of the electrodeless bulb 5,for transmitting the microwave supplied through the waveguide 4, andreflecting the light generated by the electrodeless bulb 5, and acooling fan 9 disposed at one side of the casing 1, for cooling themagnetron 2 and the high voltage generator 3.

The electrodeless bulb 5 includes a light emitting unit 5 a made ofquartz in a globular shape with an inside space, and disposed outsidethe casing 1, and a supporting unit 5 b formed in a rod shape extendedfrom the light emitting unit 5 a, for supporting the light emitting unit5 a in the casing 1.

The main discharge material, the discharge assistant material and thedischarge catalyst material are filled in the inside space of the lightemitting unit 5 a under a predetermined pressure, for generating plasmaand emitting light.

The supporting unit 5 b is coupled to a rotation shaft of a bulb motor Minstalled in the casing 1 through the reflector 8.

Reference numeral 8 a denotes a bulb through hole, and M2 denotes a fanmotor for rotating the cooling fan 9.

The operation of the conventional electrodeless lighting system will nowbe described.

When a driving signal is inputted to the high voltage generator 3according to a command of a control unit, the high voltage generator 3boosts AC power and supplies the high voltage to the magnetron 2, andthe magnetron 2 generates microwave having a very high frequency by thehigh voltage. The microwave is resonated in the resonator 6 through thewaveguide 4, for discharging the main discharge material filled in theelectrodeless bulb 5. When the main discharge material is excited togenerate plasma, light is generated with an intrinsic dischargespectrum. The light is reflected to the front by the reflecting shade 7and the reflector 8, thereby lightening the space.

The discharge assistant material filled in the light emitting unit 5 awith the main discharge material is discharged before the main dischargematerial is discharged by the microwave, thereby generating plasma inthe light emitting unit 5 a. The discharge catalyst material also filledin the light emitting unit 5 a serves to rapidly discharge the maindischarge material or the discharge assistant material at the initialstage of lighting.

As described above, the conventional electrodeless lighting system hasemployed mercury as the discharge catalyst material. As mercury turnsout to be an environmental contaminant, efforts have been made not touse mercury. However, if mercury is not used as the discharge catalystmaterial, initial discharge of the filled material is delayed, and ifintensity of an externally-applied electric field is not uniform, adischarge error occurs. As a result, reliability of the electrodelesslighting system is seriously reduced.

DISCLOSURE OF THE INVENTION

Therefore, an object of the present invention is to provide anelectrodeless bulb, and an electrodeless lighting system having the samewhich can easily and uniformly carry out initial discharge without usingan environmental contaminant such as mercury.

To achieve these and other advantages and in accordance with the purposeof the present invention, as embodied and broadly described herein,there is provided an electrodeless bulb, including: a light emittingunit having an airtight inside space; a main discharge material filledin the inside space of the light emitting unit and discharged bymicrowave, for emitting light; a discharge assistant material filled inthe light emitting unit, for forming plasma in the inside space beforethe main discharge material generates plasma; and a discharge catalystmaterial filled in the light emitting unit, for inducing initialdischarge of the main discharge material and the discharge assistantmaterial.

According to another aspect of the present invention, there is providedan electrodeless bulb, including: a light emitting unit having anairtight inside space filled with a discharge material, and emittinglight as the discharge material is discharged by microwave to generateplasma; and an auxiliary light emitting unit formed outside the lightemitting unit with an airtight inside space, a discharge assistantmaterial being filled in the inside space, for forming plasma in theinside space of the light emitting unit before the discharge material ofthe light emitting unit is discharged.

According to yet another aspect of the present invention, there isprovided an electrodeless lighting system, including: a magnetronmounted in a casing, for generating microwave; a waveguide connected toan outlet unit of the magnetron, for transmitting the microwavegenerated by the magnetron; an electrodeless bulb including a lightemitting unit having an airtight inside space filled with a dischargematerial, and emitting light as the discharge material is discharged bythe microwave to generate plasma, and a supporting unit extended fromthe outer circumference of the light emitting unit; a resonator housingthe electrodeless bulb and being connected to an outlet of thewaveguide, the resonator resonating the microwave transmitted throughthe waveguide with a predetermined resonating frequency; and a reflectormounted in the resonator, for transmitting the light generated by theelectrodeless bulb, the supporting unit of the electrodeless bulbpassing through the reflector, wherein an auxiliary light emitting unithaving an airtight inside space is formed outside the light emittingunit of the electrodeless bulb, and filled with a discharge assistantmaterial for forming plasma in the inside space of the light emittingunit before the discharge material of the light emitting unit isdischarged.

In accordance with the present invention, the discharge assistantmaterial and the discharge catalyst material are filled in the insidespace of the light emitting unit and the inside space of the auxiliarylight emitting unit formed on the outer circumference of the lightemitting unit. Accordingly, the discharge assistant material and thedischarge catalyst material are rapidly discharged by the electric fieldformed in the resonator, which eases initial lighting of the maindischarge material of the light emitting unit and reduces the lightingtime of the light emitting unit.

The foregoing and other objects, features, aspects and advantages of thepresent invention will become more apparent from the following detaileddescription of the present invention when taken in conjunction with theaccompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the invention and are incorporated in and constitute apart of this specification, illustrate embodiments of the invention andtogether with the description serve to explain the principles of theinvention.

In the drawings:

FIG. 1 is a cross-sectional view illustrating a conventionalelectrodeless lighting system having an electrodeless bulb;

FIG. 2 is a cross-sectional view illustrating an electrodeless lightingsystem having an electrodeless bulb in accordance with a firstembodiment of the present invention;

FIG. 3 is a cross-sectional view illustrating an electrodeless lightingsystem having an electrodeless bulb in accordance with a secondembodiment of the present invention;

FIG. 4 is a cross-sectional view illustrating one example of theelectrodeless bulb in accordance with the second embodiment of thepresent invention;

FIG. 5 is a cross-sectional view illustrating a modified example of theelectrodeless bulb in accordance with the second embodiment of thepresent invention;

FIG. 6 is a cross-sectional view illustrating another modified exampleof the electrodeless bulb in accordance with the second embodiment ofthe present invention;

FIG. 7 is a cross-sectional view illustrating yet another modifiedexample of the electrodeless bulb in accordance with the secondembodiment of the present invention; and

FIG. 8 is a cross-sectional view illustrating yet another modifiedexample of the electrodeless bulb in accordance with the secondembodiment of the present invention.

MODES FOR CARRYING OUT THE PREFERRED EMBODIMENTS

Reference will now be made in detail to the preferred embodiments of thepresent invention, examples of which are illustrated in the accompanyingdrawings.

FIG. 2 is a cross-sectional view illustrating an electrodeless lightingsystem having an electrodeless bulb in accordance with a firstembodiment of the present invention.

As illustrated in FIG. 2, the electrodeless lighting system includes amagnetron 2 mounted in a casing 1, for generating microwave, a waveguide4 connected to an outlet unit of the magnetron 2, for transmitting themicrowave generated by the magnetron 2, an electrodeless bulb 10 foremitting light as plasma is generated by the microwave transmittedthrough the waveguide 4, a resonator 6 covered on the front portions ofthe waveguide 4 and the electrodeless bulb 10, for resonating themicrowave with a predetermined resonating frequency, a reflecting shade7 for housing the resonator 6, and intensively reflecting the lightgenerated by the electrodeless bulb 10 straight, a reflector 8 mountedin the resonator 6 and positioned at the rear side of the electrodelessbulb 5, for reflecting the light generated by the electrodeless bulb 5,and a cooling fan 9 disposed at one side of the casing 1, for coolingthe magnetron 2 and a high voltage generator 3.

The resonator 6 is formed in a mesh shape to block the microwave andtransmit the light emitted from the electrodeless bulb 10. The reflector8 is made of a disc-shaped dielectric, for transmitting the microwavesupplied through the waveguide 4, and reflecting the light generated bythe electrodeless bulb 10. A bulb through hole 8 a is formed at thecenter of the reflector 8, so that a supporting unit 12 of theelectrodeless bulb 10 can pass through the bulb through hole 8 a.

The electrodeless bulb 10 includes a light emitting unit 11 formed in aglobular or cylindrical shape with an inside space 11 a, and disposedoutside the casing 1, and a supporting unit 12 formed in a rod shapeextended from the light emitting unit 11, for supporting the lightemitting unit 11 in the casing 1.

The light emitting unit 11 is made of quartz showing high opticaltransmissivity and low dielectric loss. A main discharge material and adischarge assistant material, or the main discharge material, thedischarge assistant material and a discharge catalyst material exceptmercury are filled in the inside space 11 a of the light emitting unit11.

Sulfur, halogen compound or selenium is used as the main dischargematerial.

An inert gas such as Ar, Xe or Kr is used as the discharge assistantmaterial.

A metal material which can generate an arc by reflecting the microwaveor radiate electrons by itself can be used as the discharge catalystmaterial. Generally, the metal material contains at least one of W, Re,Ta, Ba, Sb, In, Cd, Zn, Ge, As, Tl, Bi, Sc, Ti and Zr.

In addition, Ne can be used as the discharge catalyst material.Preferably, a mixture rate of Ne ranges from 30 to 50% of the dischargeassistant material to improve efficiency of light emission.

Same drawing reference numerals are used for the same elements even indifferent drawings.

The operation of the electrodeless lighting system in accordance withthe present invention will now be described.

According to a command of a control unit, the magnetron 2 is operated togenerate microwave having a very high frequency. The microwave isradiated to the resonator 6 through the waveguide 4, for forming astrong electric field. As the main discharge material and the dischargeassistant material filled in the inside space 11 a of the light emittingunit 11 of the electrodeless bulb 10 are excited to continuouslygenerate plasma, light is generated with an intrinsic dischargespectrum. The light is reflected to the front by the reflecting shade 7and the reflector 8, thereby lightening the space.

If the metal having high microwave reflection performance and selfelectron radiation performance, or a mixture of Ne and Ar forfacilitating initial discharge is filled in the inside space 11 a of thelight emitting unit 11 of the electrodeless bulb 10, a success ratio ofinitial lighting considerably increases. Especially, when Ne and Ar aremixed, atom generation possibility of Ne and Ar increases. Therefore,lighting efficiency can be more improved by using UV energy generated byNe.

In the above embodiment, the discharge assistant material and thedischarge catalyst material have been filled in the light emitting unit11 of the electrodeless bulb 10. In this embodiment, an auxiliary lightemitting unit 13 having an airtight inside space 13 a is formed outsidethe light emitting unit 11, and the discharge assistant material and thedischarge catalyst material are filled in the inside space 13 a of theauxiliary light emitting unit 13.

As illustrated in FIGS. 3 to 5, the auxiliary light emitting unit 13 canbe formed on the outer circumference of the light emitting unit 11. Asshown in FIGS. 6 and 7, the auxiliary light emitting unit 13 can beformed in the supporting unit 12. As shown in FIG. 8, the auxiliarylight emitting unit 13 can be formed in the light emitting unit 11 andthe supporting unit 12, respectively. In addition, the auxiliary lightemitting unit 13 can be incorporated or assembled with the lightemitting unit 11 or the supporting unit 12.

In the case that the auxiliary light emitting unit 13 is formed on theouter circumference of the light emitting unit 11, as shown in FIG. 4,the auxiliary light emitting unit 13 can be positioned in a straightline from the supporting unit 12 by considering eccentricity in rotationof the electrodeless bulb 10, and as shown in FIG. 5, the auxiliarylight emitting unit 13 can be positioned within ±180° (+90° in thedrawing) from the supporting unit 12 by considering light shading to thelight emitting unit 11.

When the auxiliary light emitting unit 13 is formed in the supportingunit 12, as shown in FIG. 6, the auxiliary light emitting unit 13 isformed at the middle portion of the supporting unit 12 to overlap withthe bulb through hole 8 a of the reflector 8, so that a strong electricfield can be concentrated on the auxiliary light emitting unit 13. Thelength L of the auxiliary light emitting unit 13 is larger than thethickness t of the reflector 8.

As depicted in FIG. 8, the auxiliary light emitting unit 13 can beformed on the boundary between the light emitting unit 11 and thesupporting unit 12.

The main discharge material, the discharge assistant material and thedischarge catalyst material of this embodiment are identical to those ofthe above-described embodiment, and thus detailed explanations thereofare omitted.

In the electrodeless lighting system, since the discharge assistantmaterial and the discharge catalyst material are also filled in theinside space 13 a of the auxiliary light emitting unit 13 formed on theouter circumference of the light emitting unit 11, the dischargeassistant material and the discharge catalyst material are rapidlydischarged by the electric field generated in the resonator 6.Accordingly, initial lighting of the main discharge material of thelight emitting unit 11 is facilitated, and the lighting time of thelight emitting time 11 is shortened. Especially, when the auxiliarylight emitting unit 13 is formed around the bulb through hole 8 a of thereflector 8, the discharge assistant material and the discharge catalystmaterial filled in the inside space 13 a of the auxiliary light emittingunit 13 formed in the supporting unit 12 are rapidly discharged by thestrong electric field formed on the bulb through hole 8 a, therebyremarkably reducing the lighting time of the light emitting unit 11.

The present invention provides the eco-friendly lighting system havinghigh optical efficiency, by rapidly performing the initial lighting orre-lighting without using mercury.

As the present invention may be embodied in several forms withoutdeparting from the spirit or essential characteristics thereof, itshould also be understood that the above-described embodiments are notlimited by any of the details of the foregoing description, unlessotherwise specified, but rather should be construed broadly within itsspirit and scope as defined in the appended claims, and therefore allchanges and modifications that fall within the metes and bounds of theclaims, or equivalence of such metes and bounds are therefore intendedto be embraced by the appended claims.

1. An electrodeless bulb, comprising: a light emitting unit having anairtight inside space; a main discharge material filled in the insidespace of the light emitting unit and discharged by microwave, foremitting light; a discharge assistant material filled in the lightemitting unit, for forming plasma in the inside space before the maindischarge material generates plasma; and a discharge catalyst materialfilled in the light emitting unit, for inducing initial discharge of themain discharge material and the discharge assistant material.
 2. Theelectrodeless bulb as claimed in claim 1, wherein the discharge catalystmaterial is metal.
 3. The electrodeless bulb as claimed in claim 2,wherein the metal comprises at least one of W, Re, Ta, Ba, Sb, In, Cd,Zn, Ge, As, Tl, Bi, Sc, Ti and Zr.
 4. The electrodeless bulb as claimedin claim 1, wherein the discharge catalyst material is Ne.
 5. Theelectrodeless bulb as claimed in claim 1, wherein metal and Ne arefilled as the discharge catalyst material.
 6. An electrodeless bulb,comprising: a light emitting unit having an airtight inside space filledwith a discharge material, and emitting light as the discharge materialis discharged by microwave to generate plasma; and an auxiliary lightemitting unit formed outside the light emitting unit with an airtightinside space, a discharge assistant material being filled in the insidespace, for forming plasma in the inside space of the light emitting unitbefore the discharge material of the light emitting unit is discharged.7. The electrodeless bulb as claimed in claim 6, wherein the dischargeassistant material is Ar.
 8. The electrodeless bulb as claimed in claim6, wherein a discharge catalyst material for inducing initial dischargeof the discharge assistant material is filled in the auxiliary lightemitting unit.
 9. The electrodeless bulb as claimed in claim 8, whereinthe discharge catalyst material is metal.
 10. The electrodeless bulb asclaimed in claim 9, wherein the metal comprises at least one of W, Re,Ta, Ba, Sb, In, Cd, Zn, Ge, As, Tl, Bi, Sc, Ti and Zr.
 11. Theelectrodeless bulb as claimed in claim 8, wherein the discharge catalystmaterial is Ne.
 12. The electrodeless bulb as claimed in claim 8,wherein metal and Ne are filled as the discharge catalyst material. 13.An electrodeless lighting system, comprising: a magnetron mounted in acasing, for generating microwave; a waveguide connected to an outletunit of the magnetron, for transmitting the microwave generated by themagnetron; an electrodeless bulb including a light emitting unit havingan airtight inside space filled with a discharge material, and emittinglight as the discharge material is discharged by the microwave togenerate plasma, and a supporting unit extended from the outercircumference of the light emitting unit; a resonator housing theelectrodeless bulb and being connected to an outlet of the waveguide,the resonator resonating the microwave transmitted through the waveguidewith a predetermined resonating frequency; and a reflector mounted inthe resonator, for transmitting the light generated by the electrodelessbulb, the supporting unit of the electrodeless bulb passing through thereflector, wherein an auxiliary light emitting unit having an airtightinside space is formed outside the light emitting unit of theelectrodeless bulb, and filled with a discharge assistant material forforming plasma in the inside space of the light emitting unit before thedischarge material of the light emitting unit is discharged.
 14. Theelectrodeless lighting system as claimed in claim 13, wherein theauxiliary light emitting unit is formed on the outer circumference ofthe light emitting unit as a single body.
 15. The electrodeless lightingsystem as claimed in claim 14, wherein the auxiliary light emitting unitis formed in a straight line from the supporting unit.
 16. Theelectrodeless lighting system as claimed in claim 14, wherein theauxiliary light emitting unit is formed within ±180° from the supportingunit.
 17. The electrodeless lighting system as claimed in claim 13,wherein the auxiliary light emitting unit is formed in the supportingunit.
 18. The electrodeless lighting system as claimed in claim 17,wherein the length of the auxiliary light emitting unit overlaps withthe thickness of the reflector.
 19. The electrodeless lighting system asclaimed in claim 13, wherein the discharge assistant material is Ar. 20.The electrodeless lighting system as claimed in claim 13, wherein adischarge catalyst material for inducing initial discharge of thedischarge assistant material is filled in the auxiliary light emittingunit.
 21. The electrodeless lighting system as claimed in claim 20,wherein the discharge catalyst material is metal.
 22. The electrodelesslighting system as claimed in claim 21, wherein the metal comprises atleast one of W, Re, Ta, Ba, Sb, In, Cd, Zn, Ge, As, Tl, Bi, Sc, Ti andZr.
 23. The electrodeless lighting system as claimed in claim 20,wherein the discharge catalyst material is Ne.
 24. The electrodelesslighting system as claimed in claim 20, wherein metal and Ne are filledas the discharge catalyst material.